New advances in magnetic resonance imaging (MRI) show enormous potential for a broad range ot new clinical and research applications including high-speed cardiovascular imaging, functional brain imaging, and contrast-sensitive image-guided intervention. They promise important advances in the assessment and treatment of cardiovascular disease, cancer and brain function. Central to their success are the dual demands of imaging speed and signal-to-noise ratio (SNR). Core biotechnology research that significantly advances MRJ speed and SNR are pivotal to progress and could impact new MRI applications across-the-board. This proposal, responsive to PAR-99-009 for Bioengineering Research, will directly advance MRI speed and SNR with innovative research in fourkey areas: the MRI gradient systems; high-speed multi-channel MRI receivers; new high-speed relaxation time (Ti) measurements and imaging; and the design of MRI detector coil systems that deliver the ultimate intrinsic SNR (UISNR)-the maximum that can be had. Specifically, we propose to develop compact, highly-efficient surface MRI gradient modules that can significantly increase gradient strength by more than an order of magnitude, and reduce gradient rise-times, and to develop algorithms to correct gradient nonlinearity. We will demonstrate the gradient advantages in a pilot study of diffusion MRI in acutestroke. We will develop a high-speed multi-channel receiver system with new analytic reconstruction methods for sensitivity-encoding to achieve manifold reductions in the minimum scan-time, and to realize the speed gains from the other projects, and we will demonstrate this with real-time MRT stress-testing of patients with ischemia. Ti relaxation is key to MRI contrast, and we propose new methods that promise dramatic reductions in Ti measurement times, Ti imaging, and we will demonstrate its potential for temperature monitoring during RF ablation therapy. andin human Ti studies. Finally, we introduced the USINR concept, and will now develop tools for designing coils that yield the UISNR, and build them for the head, heart, and abdomen, and will compare their performance to existingcoils. We hypothesize that the integration of radical redesigns of gradient, MRI detector coils, and high-speed contrast-sensitive MRI, will yield simultaneous performance gains that will provide truly new opportunities for clinical diagnostic and interventional research. The work will be implemented at 1 .5T and will directly and positively benefit 21 other funded research grants at this institution, with broad potential benefit to noninvasive imaging in a wide range of patients and diseases.